End effector with a clamp arm assembly and blade

ABSTRACT

An end effector of a surgical instrument may generally comprise a blade, and a clamp arm assembly comprising a clamp arm movable between an open position and a closed position relative to the blade, and at least one camming member rotationally attached to the clamp arm, wherein the at least one camming member is configured to rotate relative to the blade as the clamp arm moves from the open position to the closed position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application claiming priority under 35U.S.C. §121 to U.S. patent application Ser. No. 13/833,706, entitledSURGICAL INSTRUMENT WITH MULTIPLE CLAMPING MECHANISMS, filed Mar. 15,2013, which issued as U.S. Pat. No. 9,241,728 on Jan. 26, 2016, theentire disclosure of which is hereby incorporated by reference herein.

BACKGROUND

1. Field of the Invention

The present application generally relates to medical devices andmethods, and in particular, surgical instruments configured to weldand/or incise tissue.

2. Description of the Related Art

In various circumstances, a surgical instrument can be configured toapply energy to tissue in order to treat and/or destroy the tissue. Incertain circumstances, a surgical instrument can comprise one or moreelectrodes which can be positioned against and/or positioned relative tothe tissue such that electrical current can flow through the electrodesand into the tissue. The surgical instrument can further comprise anelectrical input, a supply conductor electrically coupled with theelectrodes, and/or a return conductor which can be configured to allowcurrent to flow from the electrical input, through the supply conductor,through the electrodes and tissue, and then through the return conductorto an electrical output, for example. In various circumstances, theenergy can generate heat within the captured tissue to create one ormore hemostatic seals within the tissue. Such embodiments may beparticularly useful for sealing blood vessels, for example. The surgicalinstrument can comprise an ultrasonic blade, connected to an ultrasonictransducer, to couple mechanical vibration to tissue and create one ormore hemostatic seals and divide the tissue simultaneously. Suchembodiments may be particularly useful for sealing and dividing bloodvessels, for example. Furthermore, other energy modalities may becontemplated, but not limited to, microwave, laser, thermal, and highintensity focused ultrasound. The surgical instrument can furthercomprise a cutting member which can be moved relative to the tissue andelectrodes in order to transect the tissue.

The foregoing discussion is intended only to illustrate various aspectsof the related art in the field of the invention at the time, and shouldnot be taken as a disavowal of claim scope.

SUMMARY

In various embodiments, a surgical instrument may generally comprise ashaft comprising a proximal end and a distal end, an ultrasonicwaveguide at least partially positioned within the shaft, the waveguidehaving a proximal end and a distal end, an ultrasonically actuated bladepositioned at the distal end of the waveguide, and a clamp arm assemblypivotally connected to the distal end of the shaft, wherein the clamparm assembly comprises at least two camming members rotationallyattached to a clamp arm, wherein the clamp arm is movable between anopen position and a closed position relative to the blade to compresstissue intermediate the clamp arm and the blade when in the closedposition, and wherein the at least two camming members rotate relativeto the clamp arm to separate tissue layers when the clamp arm movesbetween the open position and the closed position.

In various embodiments, an end effector may generally comprise a blade,and a clamp arm assembly configured to pivot relative to the blade,wherein the clamp arm assembly comprises a clamp arm movable between anopen position and a closed position to compress tissue or a vesselintermediate the clamp arm assembly and the blade when in the closedposition, and at least one camming member rotationally attached to theclamp arm, wherein the at least one camming member is configured torotate relative to the blade as the clamp arm moves from the openposition to the closed position to separate layers of the tissue or thevessel.

In various embodiments, an end effector may generally comprise a blade,and a clamp arm assembly comprising a clamp arm movable between an openposition and a closed position relative to the blade, and at least onecamming member rotationally attached to the clamp arm, wherein the atleast one camming member is configured to rotate relative to the bladeas the clamp arm moves from the open position to the closed position.

BRIEF DESCRIPTION OF THE FIGURES

Various features of the embodiments described herein are set forth withparticularity in the appended claims. The various embodiments, however,both as to organization and methods of operation, together withadvantages thereof, may be understood in accordance with the followingdescription taken in conjunction with the accompanying drawings asfollows.

FIG. 1 includes a side elevational view of a surgical instrumentaccording to various embodiments.

FIG. 2 includes a perspective view of the end effector of the device ofFIG. 1, in an open configuration according to various embodiments.

FIG. 3 includes another perspective view of the end effector of thedevice of FIG. 1, in an open configuration according to variousembodiments.

FIG. 4 includes a cross-sectional end view of the end effector of FIG.2, in a closed configuration and with the blade in a distal positionaccording to various embodiments.

FIG. 4A includes a surgical instrument comprising an end effectorcomprising roller bearings according to various embodiments.

FIG. 5 includes a surgical instrument comprising a trigger assembly invarious positions according to various embodiments.

FIG. 6 includes a surgical instrument comprising a trigger bypassmechanism according to various embodiments.

FIG. 7 includes the trigger bypass mechanism illustrated in FIG. 6.

FIGS. 8A-G include a surgical instrument comprising a trigger assemblyin various positions according to various embodiments.

FIGS. 9A-G include a surgical instrument comprising a trigger assemblyin various positions according to various embodiments.

FIGS. 10A-D include a surgical instrument comprising a trigger assemblyin various positions according to various embodiments.

FIGS. 11A-C include a surgical instrument comprising a trigger assemblyin various positions according to various embodiments.

FIG. 12 includes a cross sectional view of a rear yoke pin path in asurgical instrument according to various embodiments

FIG. 13 includes a cross sectional view of a rear yoke pin path in asurgical instrument according to various embodiments

FIGS. 14A-C include a surgical instrument comprising a trigger assemblyin various positions according to various embodiments.

FIGS. 15A-K include a surgical instrument comprising a trigger assemblyin various positions according to various embodiments.

FIG. 16 includes a surgical instrument comprising a trigger assemblyaccording to various embodiments.

FIGS. 17A-H include cross-sectional views of a portion of a vesselsubjected to a compressive force according to various embodiments.

FIGS. 18A and 18B include a surgical instrument comprising an endeffector in various positions according to various embodiments.

FIGS. 19A and 19B include a side elevational view of the handle assemblyof a surgical instrument with a housing half removed according tovarious embodiments.

FIG. 20 includes an end effector comprising rotational featuresaccording to various embodiments.

FIGS. 21A and 21B includes a camming member comprising a protrusionaccording to various embodiments

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate various embodiments of the invention, in one form, and suchexemplifications are not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION

Various embodiments are directed to apparatuses, systems, and methodsfor the treatment of tissue. Numerous specific details are set forth toprovide a thorough understanding of the overall structure, function,manufacture, and use of the embodiments as described in thespecification and illustrated in the accompanying drawings. It will beunderstood by those skilled in the art, however, that the embodimentsmay be practiced without such specific details. In other instances,well-known operations, components, and elements have not been describedin detail so as not to obscure the embodiments described in thespecification. Those of ordinary skill in the art will understand thatthe embodiments described and illustrated herein are non-limitingexamples, and thus it can be appreciated that the specific structuraland functional details disclosed herein may be representative and do notnecessarily limit the scope of the embodiments, the scope of which isdefined solely by the appended claims.

Reference throughout the specification to “various embodiments,” “someembodiments,” “one embodiment,” or “an embodiment”, or the like, meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.Thus, appearances of the phrases “in various embodiments,” “in someembodiments,” “in one embodiment,” or “in an embodiment”, or the like,in places throughout the specification are not necessarily all referringto the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment may be combined, in whole or in part, with the featuresstructures, or characteristics of one or more other embodiments withoutlimitation.

It will be appreciated that the terms “proximal” and “distal” may beused throughout the specification with reference to a clinicianmanipulating one end of an instrument used to treat a patient. The term“proximal” refers to the portion of the instrument closest to theclinician and the term “distal” refers to the portion located furthestfrom the clinician. It will be further appreciated that for concisenessand clarity, spatial terms such as “vertical,” “horizontal,” “up,” and“down” may be used herein with respect to the illustrated embodiments.However, surgical instruments may be used in many orientations andpositions, and these terms are not intended to be limiting and absolute.

Various embodiments of systems and methods relate to creating thermal“welds” or “fusion” within native tissue volumes. The alternative termsof tissue “welding” and tissue “fusion” may be used interchangeablyherein to describe thermal treatments of a targeted tissue volume thatresult in a substantially uniform fused-together tissue mass, forexample, in welding blood vessels that exhibit substantial burststrength immediately post-treatment. The strength of such welds isparticularly useful for (i) permanently sealing blood vessels in vesseltransection procedures; (ii) welding organ margins in resectionprocedures; (iii) welding other anatomic ducts wherein permanent closureis required; and also (iv) for performing vessel anastomosis, vesselclosure or other procedures that join together anatomic structures orportions thereof. The welding or fusion of tissue as disclosed herein isto be distinguished from “coagulation”, “hemostasis” and other similardescriptive terms that generally relate to the collapse and occlusion ofblood flow within small blood vessels or vascularized tissue. Forexample, any surface application of thermal energy can cause coagulationor hemostasis-but does not fall into the category of “welding” as theterm is used herein. Such surface coagulation does not create a weldthat provides any substantial strength in the treated tissue.

At the molecular level, the phenomena of truly “welding” tissue asdisclosed herein may result from the thermally-induced denaturation ofcollagen and other protein molecules in a targeted tissue volume tocreate a transient liquid or gel-like proteinaceous amalgam. A selectedenergy density is provided in the targeted tissue to cause hydrothermalbreakdown of intra- and intermolecular hydrogen crosslinks in collagenand other proteins. The denatured amalgam is maintained at a selectedlevel of hydration-without desiccation-for a selected time intervalwhich can be very brief. The targeted tissue volume is maintained undera selected very high level of mechanical compression to insure that theunwound strands of the denatured proteins are in close proximity toallow their intertwining and entanglement. Upon thermal relaxation, theintermixed amalgam results in protein entanglement as re-crosslinking orrenaturation occurs to thereby cause a uniform fused-together mass.

Ultrasonic surgical instruments are finding increasingly widespreadapplications in surgical procedures by virtue of the unique performancecharacteristics of such instruments. Depending upon specific instrumentconfigurations and operational parameters, ultrasonic surgicalinstruments can provide substantially simultaneous cutting of tissue andhemostasis by coagulation, desirably minimizing patient trauma. Thecutting action is typically effected by an end effector or blade tip atthe distal end of the instrument, which transmits ultrasonic energy totissue brought into contact with the end effector. Ultrasonicinstruments of this nature can be configured for open surgical use,laparoscopic or endoscopic surgical procedures includingrobotic-assisted procedures.

Ultrasonic surgical instruments have been developed that include a clampmechanism to press tissue against the blade of the end effector in orderto couple ultrasonic energy to the tissue of a patient. Such anarrangement (sometimes referred to as a clamp coagulator shears or anultrasonic transector) is disclosed in U.S. Pat. Nos. 5,322,055,5,873,873, and 6,325,811, all of which are incorporated herein byreference in their entireties. The surgeon activates the clamp arm topress the clamp pad against the blade by squeezing on the handgrip orhandle.

Some current ultrasonic shears devices utilize tissue engaging pads orclamp pads that close in parallel with the surface of the blade. By thisconstruction, tissue is grasped between the clamp pad and the blade. Theclamp pad may comprise a low coefficient of friction polymer material,or any other suitable low-friction material. Although these designs havebeen adequate, they tend to suffer from longevity issues since the clamppads tend to deteriorate over long surgical procedures. Additionally,newer designs of clamp coagulator shears increase blade amplitude and/orthe loading of the clamp pad against the tissue and blade and overwhelmthe clamp pad material, resulting in less than required clamp pad life.The clamp pad material limits the amount of force that may be appliedagainst the tissue and blade, which in turn limits the tissue thicknessor vessel size that some current clamp coagulator shears may effectivelycut and coagulate.

It would be desirable to provide electrosurgical instruments thatovercome some of the deficiencies of current ultrasonic surgicalinstruments. Various embodiments of the electrosurgical instrumentsdescribed herein may overcome some of those deficiencies.

Enhancing the ability to seal vessels may be accomplished by placing theadventitial layers of the opposing sides of a coapted vessel in directcontact with each other. Preventing this direct contact is commonly themuscular (entima) layer of the vessel. The muscular layers may be“split” within a vessel without compromising the adventitia by applyinga sufficient compressive force. The muscular layers may retract enoughto allow direct adventitial contact. The direct adventitial sealsdemonstrate higher burst pressures. In various embodiments, anelectrosurgical device may provide variable force control to allow theuser to create a large compressive force for muscle separation and asmaller compressive force for application of ultrasonic energy andsealing and cutting.

In various embodiments, electrosurgical instruments may be configured toprovide multiple trigger positions to deliver multiple levels ofcompressive force to the tissue. The compressive force may be generallyestablished by a handle using one of two user-selectable clamping modesto provide variable force control: one for cutting and coagulating smallblood vessels; and one for cutting and coagulating large blood vessels.The large vessel coagulating mode generally corresponds to a sequencewhere the end effector delivers a short-term high compressive force andthen progresses to a position of lesser compressive force. For example,in various embodiments, the lesser compressive force may be about 50% toabout 70% of the high compressive force. The high compressive force maycompress a large vessel such that the inner layers of the vessel, i.e.,the tunica intima and tunica media, are extruded and separated and onlythe outer layer of the vessel, i.e., the tunica adventitia, resideswithin the end effector.

Without wishing to be bound to any particular theory, it is believedthat the adventitia contributes most significantly to the seal strengthof an ultrasonically transected vessel, and the inner layers of thevessel contribute very little to the seal strength and, in fact, tend toflatten and structurally counteract the adventitia seal. Accordingly,electrosurgical instruments may be configured to provide a highcompressive force to mechanically extrude the inner layers of the vesseland a low compressive force to allow direct adventitial contact and anadventitia-to-adventitia seal. Various embodiments of electrosurgicalinstruments described herein may provide certain advantages over currentultrasonic shears devices, including one or more of the following:obtaining a seal at a more manageable, lower clamping force; obtaining aseal at a lower generator drive power; lower generator powerrequirements; utilizing less durable clamp pad materials; improved largevessel sealing; improved clamp pad life; improved ergonomics by onlyusing the high clamp force, which corresponds to high input force, whenrequired; improved efficiency; and improved cost savings.

An electrosurgical instruments can be configured to supply energy, suchas electrical energy, ultrasonic energy, and/or heat energy, forexample, to the tissue of a patient. For example, various embodimentsdisclosed herein provide electrosurgical jaw structures adapted fortransecting captured tissue between the jaws and for contemporaneouslywelding or sealing the captured tissue margins with controlledapplication of RF energy. In various embodiments, the electrosurgicaljaw structures may be adapted to coagulate the captured tissues ratherthan weld the captured tissue. Electrosurgical instruments may also beconfigured to, for example, grasp, sever, and staple tissue.Electrosurgical instruments may be configured to supply other energymodalities and/or combinations thereof, such as, for example, microwave,laser, thermal, ultrasonic and high intensity focused ultrasound. Allsuch arrangements and implementations are intended to be within thescope of this disclosure.

In various embodiments, referring to FIG. 1, an electrosurgicalinstrument 10 may comprise a hand piece 20, a shaft 30 extendingdistally from hand piece 20, and an end effector 40 disposed at a distalend of shaft 30. Hand piece 20 may comprise a pistol grip 22, a pivotingtrigger 24, and an activation button 26. Trigger 24 may be pivotabletoward and away from pistol grip 22 to selectively actuate end effector40 as will be described in greater detail below. Activation button 26may be operable to selectively activate RF circuitry that is incommunication with end effector 40, as will also be described in greaterdetail below. In some versions, activation button 26 may also serve as amechanical lockout against trigger 24, such that trigger 24 cannot befully actuated unless button 26 is being pressed simultaneously.Examples of how such a lockout may be provided are disclosed in one ormore of the references cited herein. It should be understood that pistolgrip 22, trigger 24, and button 26 may be modified, substituted,supplemented, etc. in any suitable way, and that the descriptions ofsuch components herein are merely illustrative.

Shaft 30 may comprise any suitable cross-section, such as, for example,a cylindrical cross-section and/or rectangular cross-section. Shaft 30may comprise an outer sheath 32 that extends from the hand piece 20. Aproximal end of shaft 30 may be attached to the hand piece 20. Invarious embodiments, shaft 30 may be rotatable about the longitudinalaxis defined by sheath 32, relative to hand piece 20 via a knob 34. Suchrotation may provide rotation of end effector 40 and shaft 30 unitarily.In various embodiments, knob 34 may be operable to rotate end effector40 without rotating any portion of shaft 30.

In various embodiments, end effector 40 may comprise a first jaw 42 anda second jaw 44. Second jaw 44 may be substantially fixed relative toshaft 30; while first jaw 42 may pivot relative to shaft 30, toward andaway from second jaw 42. In various embodiments, actuators, such as, forexample, rods and cables, may extend through sheath 32 and be joinedwith first jaw 42 at a pivotal coupling 43 such that longitudinalmovement of the actuator through shaft 30 provides pivoting of first jaw42 relative to shaft 30 and relative to second jaw 44. In variousembodiments, jaws 42, 44 may comprise any other suitable kind ofmovement and may be actuated in any other suitable fashion. For example,as will be described in greater detail below, jaws 42, 44 may beactuated and thus closed by longitudinal translation of a firing beam 60such that actuators may simply be eliminated in certain embodiments.

In various embodiments, referring to FIGS. 2-4, first jaw 42 defines alongitudinally extending elongate slot 46 and second jaw 44 defines alongitudinally extending elongate slot 48. The top side of first jaw 42may comprise a first electrode surface 50 and the underside of secondjaw 44 may comprise a second electrode surface 52. Electrode surfaces50, 52 may be in communication with an electrical source 80 via one ormore conductors (not shown) that extend along the length of shaft 30.Electrical source 80 may be operable to deliver RF energy to firstelectrode surface 50 at a first polarity and to second electrode surface52 at a second (opposite) polarity, such that RF current flows betweenelectrode surfaces 50, 52 and thereby through tissue captured betweenjaws 42, 44. In various embodiments, firing beam 60 may serve as anelectrical conductor that cooperates with electrode surfaces 50, 52,e.g., as a ground return for delivery of bipolar RF energy capturedbetween jaws 42, 44. Electrical source 80 may be external toelectrosurgical instrument 10 or may be integral with electrosurgicalinstrument 10, e.g., in hand piece 20. A controller 82 may regulatedelivery of power from electrical source 80 to electrode surfaces 50,52. Controller 82 may be external to electrosurgical instrument 10 ormay be integral with electrosurgical instrument 10, e.g., in hand piece20. It should also be understood that electrode surfaces 50, 52 may beprovided in a variety of alternative locations, configurations, andrelationships.

Referring to FIG. 4, the lower side of first jaw 42 may comprise alongitudinally extending recess 58 adjacent to slot 46 and the upperside of second jaw 44 may comprise a longitudinally extending recess 58adjacent to slot 48. FIG. 2 shows the upper side of first jaw 42including a plurality of teeth serrations 46. It should be understoodthat the lower side of second jaw 44 may include complementaryserrations that nest with serrations 46 to enhance gripping of tissuecaptured between jaws 42, 44 without necessarily tearing the tissue.FIG. 3 shows an example of serrations 46 in first jaw 42 as mainlyrecesses; with serrations 48 in second jaw 44 as mainly protrusions. Ofcourse, serrations 46, 48 may take any other suitable form or may besimply omitted altogether. It should also be understood that serrations46, 48 may be formed of an electrically non-conductive, or insulative,material, such as plastic, glass, and/or ceramic, for example, and mayinclude a treatment such as polytetrafluoroethylene, a lubricant, orsome other treatment to substantially prevent tissue from getting stuckto jaws 42, 44.

When jaws 42, 44 are in a closed position, shaft 30 and end effector 40may be sized and configured to fit through trocars having various innerdiameters, such that electrosurgical instrument 10 may be usable inminimally invasive surgery, though of course electrosurgical instrument10 could also be used in open and endoscopic procedures if desired. Byway of example only, shaft 30 and end effector 40 may present an outerdiameter of approximately 5 mm when jaws 42, 44 are in a closedposition. Alternatively, shaft 30 and end effector 40 may present anyother suitable outer diameter, such as, for example, from about 2 mm toabout 20 mm.

In various embodiments, either jaw 42, 44 or both of jaws 42, 44 mayinclude at least one port, passageway, conduit, and/or other featurethat is operable to draw steam, smoke, and/or other gases from thesurgical site. Such a feature may be in communication with a source ofsuction, such as, for example, an external source or a source withinhand piece 20. In addition, end effector 40 may comprise one or moretissue cooling features (not shown) that reduce the degree or extent ofthermal spread caused by end effector 40 on adjacent tissue whenelectrode surfaces 50, 52 are activated. Various suitable forms thatsuch cooling features may take will be apparent to those of ordinaryskill in the art in view of the teachings herein.

In various embodiments, end effector 40 may comprise one or more sensors(not shown) that are configured to sense a variety of parameters at endeffector 40, including but not limited to, jaw position, temperature ofadjacent tissue, electrical resistance or impedance of adjacent tissue,voltage across adjacent tissue, forces exerted on jaws 42, 44 byadjacent tissue. In various embodiments, end effector 40 may include oneor more positive temperature coefficient (PTC) thermistor bodies 54, 56,e.g., a PTC polymer, located adjacent to electrodes 50, 52 and/orelsewhere. Data from sensors may be communicated to controller 82.Controller 82 may process such data in a variety of ways. In variousembodiments, controller 82 may modulate or otherwise change the RFenergy being delivered to electrode surfaces 50, 52, based at least inpart on data acquired from one or more sensors at end effector 40. Invarious embodiments, controller 82 may alert the user to one or moreconditions via an audio and/or visual feedback device, e.g., speaker,lights, display screen, etc., based at least in part on data acquiredfrom one or more sensors at end effector 40. It should also beunderstood that some kinds of sensors need not necessarily be incommunication with controller 82, and may simply provide a purelylocalized effect at end effector 40. In various embodiments, PTCthermistor bodies 54, 56 at end effector 40 may automatically reduce theenergy delivery at electrode surfaces 50, 52 as the temperature of thetissue and/or end effector 40 increases, thereby reducing the likelihoodof overheating. In various embodiments, a PTC thermistor element may bein series with power source 80 and electrode surface 50, 52; and the PTCthermistor may provide an increased impedance to reduce flow of currentin response to temperatures exceeding a threshold. Furthermore, itshould be understood that electrode surfaces 50, 52 may be used assensors, e.g., to sense tissue impedance. Various kinds of sensors thatmay be incorporated into electrosurgical instrument 10 will be apparentto those of ordinary skill in the art in view of the teachings herein.Similarly various things that can be done with data from sensors, bycontroller 82 or otherwise, will be apparent to those of ordinary skillin the art in view of the teachings herein. Other suitable variationsfor end effector 40 will also be apparent to those of ordinary skill inthe art in view of the teachings herein.

In various embodiments, referring to FIGS. 2-4, electrosurgicalinstrument may comprise a firing beam 60 that is longitudinally movablealong part of the length of end effector 40. Firing beam 60 may becoaxially positioned within shaft 30, extends along the length of shaft30, and translates longitudinally within shaft 30, though it should beunderstood that firing beam 60 and shaft 30 may have any other suitablerelationship. Firing beam 60 may comprise a sharp distal blade 64, anupper flange 62, and a lower flange 66. As illustrated in FIG. 4, distalblade 64 extends through slots 46, 48 of jaws 42, 44, with upper flange62 being located above jaw 44 in recess 59 and lower flange 66 beinglocated below jaw 42 in recess 58. The configuration of distal blade 64and flanges 62, 66 provides an “I-beam” type of cross section at thedistal end of firing beam 60. In various embodiments, flanges 62, 66 mayextend longitudinally along any suitable length of firing beam 60. Invarious embodiments, flanges 62, 66 may be positioned along the exteriorof jaws 42, 44, or disposed in corresponding slots formed within jaws42, 44. For example, each jaw 42, 44 may define a “T”-shaped slot, withportions of distal blade 64 being disposed in one vertical portion ofeach “T”-shaped slot and with flanges 62, 66 being disposed in thehorizontal portions of the “T”-shaped slots. Referring to FIG. 4A, invarious embodiments, distal blade 64 may comprise at least one rollerbearing 38 to compress tissue T and/or fracture calcium formed within orexternally to the vessel. Roller bearing 38 may comprise a conicalcylinder have a decreasing diameter laterally away from distal blade 64,as shown in FIG. 4A. In various embodiments, roller bearing 38 maycomprise a conical cylinder have a increasing diameter laterally awayfrom distal blade 64. In various embodiments, roller bearing 38 maycomprise a straight cylinder. In various embodiments, roller bearing 38may comprise a curved cross-sectional shape, such as, for example, acircle and an ellipse. As shown in FIG. 4A, roller bearings 38 may bepositioned on opposing sides of distal blade 64 intermediate jaws 42,44. In various embodiments, distal blade 64 may comprise a pin (notshown) to rotate roller bearing 38 relative to distal blade 64. Invarious embodiments, distal blade may comprise a vertical slot includinga pin slideably disposed in the vertical slot to rotate roller bearing38 and/or move roller bearing 38 perpendicularly relative to distalblade 64 Various other suitable configurations and relationships will beapparent to those of ordinary skill in the art in view of the teachingsherein.

Distal blade 64 may be substantially sharp, such that distal blade 64may readily sever tissue that is captured between jaws 42, 44. Distalblade 64 may be electrically grounded to provide a return path for RFenergy as described elsewhere herein. In various embodiments, distalblade 64 may serve as an active electrode. In various embodiments,distal blade 64 may be selectively energized with ultrasonic energy,such as, for example, harmonic vibrations at about 55.5 kHz.

In various embodiments, the “I-beam” type of configuration of firingbeam 60 may provide closure of jaws 42, 44 as firing beam 60 is advanceddistally. In particular, flange 62 urges jaw 44 pivotally toward jaw 42as firing beam 60 is advanced from a proximal position, as shown inFIGS. 1-3, to a distal position, as shown in FIG. 4, by bearing againstrecess 59 formed in jaw 44. This closing effect on jaws 42, 44 by firingbeam 60 may occur before distal blade 64 reaches tissue captured betweenjaws 42, 44. Such staging of encounters by firing beam 60 may reduce theforce required to squeeze grip 24 to actuate firing beam 60 through afull firing stroke. In other words, in various embodiments, firing beam60 may have already overcome an initial resistance required tosubstantially close jaws 42, 44 on tissue before encountering resistancefrom severing the tissue captured between jaws 42, 44. Of course, anyother suitable staging may be provided.

In various embodiments, flange 62 may be configured to cam against aramp feature at the proximal end of jaw 44 to open jaw 42 when firingbeam 60 is retracted to a proximal position and to hold jaw 42 open whenfiring beam 60 remains at the proximal position. This camming capabilitymay facilitate use of end effector 40 to separate layers of tissue, toperform blunt dissections, etc., by forcing jaws 42, 44 apart from aclosed position. In various embodiments, jaws 42, 44 may be resilientlybiased to an open position by a spring or other type of resilientfeature. While jaws 42, 44 close or open as firing beam 60 istranslated, it should be understood that other embodiments may provideindependent movement of jaws 42, 44 and firing beam 60. In variousembodiments, one or more cables, rods, beams, or other features mayextend through shaft 30 to selectively actuate jaws 42, 44 independentlyof firing beam 60. Such jaw 42, 44 actuation features may be separatelycontrolled by a dedicated feature of hand piece 20. In variousembodiments, such jaw actuation features may be controlled by trigger 24in addition to having trigger 24 control firing beam 60. It should alsobe understood that firing beam 60 may be resiliently biased to aproximal position, such that firing beam 60 retracts proximally when auser relaxes their grip on trigger 24.

In various embodiments, in use, end effector 40 may be inserted into apatient via a trocar to a desired position and orientation relative toan anatomical structure within the patient. Two layers of tissue of theanatomical structure are then captured between jaws 42, 44 by squeezingtrigger 24 toward pistol grip 22. Such layers of tissue may be part ofthe same natural lumen defining anatomical structure, such as, forexample, blood vessel, portion of gastrointestinal tract, portion ofreproductive system, etc., in a patient. In various embodiments, onetissue layer may comprise the top portion of a blood vessel and theother tissue layer may comprise the bottom portion of the blood vessel,along the same region of length of the blood vessel. In variousembodiments, the fluid path through the blood vessel before use ofelectrosurgical instrument 10 may be perpendicular to the longitudinalaxis defined by end effector 40. The lengths of jaws 42, 44 may beoriented perpendicular to or at least generally transverse to the lengthof the blood vessel. As described above, flanges 62, 66 cammingly act topivot jaw 44 toward jaw 42 when firing beam 60 is actuated distally bysqueezing trigger 24 toward pistol grip 22.

In various embodiments, with tissue layers captured between jaws 42, 44,firing beam 60 may continue to advance distally by the user squeezingtrigger 24 toward pistol grip 22. As firing beam 60 advances distally,distal blade 64 simultaneously severs the clamped tissue layers,resulting in separated upper layer portions being apposed withrespective separated lower layer portions. This results in a bloodvessel being cut in a direction that is generally transverse to thelength of the blood vessel. It should be understood that the presence offlanges 62, 66 immediately above and below jaws 42, 44, respectively,may help keep jaws 42, 44 in a closed and tightly clamping position. Inparticular, flanges 62, 66 may help maintain a significantly compressiveforce between jaws 42, 44. With severed tissue layer portions beingcompressed between jaws 42, 44, electrode surfaces 50, 52 may beactivated with bipolar RF energy by the user depressing activationbutton 26. In various embodiments, electrodes 50, 52 may be selectivelycoupled with power source 80, for example by the user depressing button26, such that electrode surfaces 50, 52 of jaws 42, 44 are activatedwith a common first polarity while firing beam 60 is activated at asecond polarity that is opposite to the first polarity. Thus, a bipolarRF current flows between firing beam 60 and electrode surfaces 50, 52 ofjaws 42, 44 through the compressed regions of severed tissue layerportions. In various embodiments, electrode surface 50 has one polaritywhile electrode surface 52 and firing beam 60 both have the otherpolarity. Bipolar RF energy may be delivered by power source 80 tothermally weld the tissue layer portions on one side of firing beam 60together and the tissue layer portions on the other side of firing beam60 together.

In certain circumstances, the heat generated by activated electrodesurfaces 50, 52 can denature the collagen within the tissue layerportions and, in cooperation with compressive force provided by jaws 42,44, the denatured collagen can form a seal within the tissue layerportions. Thus, the severed ends of the natural lumen defininganatomical structure are hemostatically sealed shut, such that thesevered ends will not leak bodily fluids. In various embodiments,electrode surfaces 50, 52 may be activated with bipolar RF energy beforefiring beam 60 begins to translate distally and thus before the tissueis even severed. For example, such timing may be provided in versionswhere button 26 serves as a mechanical lockout relative to trigger 24 inaddition to serving as a switch between power source 80 and electrodesurfaces 50, 52.

While several of the teachings below are described as variations toelectrosurgical instrument 10, it should be understood that variousteachings below may also be incorporated into various other types ofdevices. By way of example only, in addition to being readilyincorporated into electrosurgical instrument 10, various teachings belowmay be readily incorporated into the devices taught in any of thereferences cited herein, other types of electrosurgical devices,alternative energy modality devices, surgical staplers, surgical clipappliers, and tissue graspers, among various other devices. Othersuitable devices into which the following teachings may be incorporatedwill be apparent to those of ordinary skill in the art in view of theteachings herein.

In various embodiments, the surgical instrument may comprise a two stageclamping mechanism configured to provide a higher clamp force to partthe muscular layer of a blood vessel and a lower clamp force to sealacross the adventitia. Without wishing to be bound to any particulartheory, it is believe that the lower clamp force facilitates the properheating rate to generate a higher strength seal across the adventitialayers relative to the higher clamp force.

In various embodiments, as shown in FIG. 5, trigger 24 may be movablerelative to hand piece 20 between an unactuated position and one or moreactuated positions. In various embodiments, trigger 24 is movablethrough a first range of motion from an unactuated position 1 to a firstactuated position 2. In various embodiments, the first range of motionmay be from an unactuated position 1 to position 3 and/or position 4,and from position 3 and/or position 4 to first actuated position 2. Invarious embodiments, trigger 24 is movable through a second range ofmotion from the first actuated position 2 to a second actuated position3. In various embodiments, trigger 24 is movable through a third rangeof motion from the second actuated position 3 to the unactuated position1. In various embodiments, trigger 24 is movable through a fourth rangeof motion from the unactuated position 1 to the third actuated position4. In various embodiments, trigger 24 is movable through a fifth rangeof motion from the third actuated position 4 to the unactuated position1. In various embodiments, the second actuated position 3 and thirdactuated position 4 may be the same or different.

In various embodiments, as described above, jaws 42, 44 may applycompressive force, or coaptation force, to tissue captured therebetween.In various embodiments, jaws 42, 44 may apply a first compressive forcewhen trigger 24 is in the first actuated position 2, a secondcompressive force when trigger 24 is in the second actuated position 3,and a third compressive force when trigger 24 is in the third actuatedposition 4. In various embodiments, referring to FIG. 5, jaws 42, 44 maybe in a closed position characterized by a first compressive force whentrigger 24 is in the first actuated position. In various embodiments,jaws 42, 44 may be in a closed position characterized by a secondcompressive force when trigger 24 is in the second actuated position. Invarious embodiments, jaws 42, 44 may be in a closed positioncharacterized by a third compressive force when trigger 24 is in thethird actuated position. In various embodiments, jaws 42, 44 may be inan open position when trigger 24 is in the unactuated position.

In various embodiments, the first compressive force, second compressiveforce, and third compressive force may be different. In variousembodiments, the first compressive force may be greater than the secondcompressive force. In various embodiments, the second compressive forcemay be greater than or equal to the third compressive force. In variousembodiments, the first compressive force, second compressive force, andthird compressive force may be individually selected from up to about 10pounds per square inch (“psi”), such as, for example, about 1 psi toabout 10 psi, about 2 psi to about 8 psi, about 3 psi to about 5 psi,and about 4 psi to about 6 psi. In various embodiments, the firstcompressive force may be about 4 psi to about 6 psi and the secondcompressive force may be about 2 psi to about 4 psi. In variousembodiments, the first compressive force may be about 6 psi and thesecond compressive force may be about 4 psi. In various embodiments, thefirst compressive force may be about 4 psi and the second compressiveforce may be about 2 psi. In various embodiments, the first compressiveforce may be about 3 psi to about 5 psi and the second compressive forcemay be about 1 psi to about 3 psi. In various embodiments, the firstcompressive force may be about 5 psi and the second compressive forcemay be about 3 psi. In various embodiments, the first compressive forcemay be about 3 psi and the second compressive force may be about 1 psi.In various embodiments, jaws 42, 44 may not apply compressive force tothe tissue when trigger 24 is in the unactuated position.

In various embodiments, electrosurgical instrument 10 may comprise atrigger assembly configured to actuate end effector 40 to providevariable compressive force to tissue captured between jaws 42, 44 whentrigger 24 is in the first actuated position, second actuated position,and/or third actuated position, as described in greater detail below. Invarious embodiments, the trigger assembly may be configured to limit thecompressive force to a first compressive force when trigger 24 is in thefirst actuated position and limit the compressive force to a secondcompressive force when trigger 24 is in the second actuated position. Invarious embodiments, the trigger assembly may be configured to limit thecompressive force to a third compressive force when trigger 24 is in thethird actuated position.

In various embodiments, electrosurgical instrument 10 may comprise atrigger assembly configured to actuate end effector 40 to providevariable compressive force to tissue captured between jaws 42, 44through the first range of motion, second range of motion, and/or thirdrange of motion, as described in greater detail below. In variousembodiments, the trigger assembly may be configured to limit thecompressive force to a first compressive force through the first rangeof motion and limit the compressive force to a second compressive forcethrough the second range of motion. In various embodiments, the triggerassembly may be configured to limit the compressive force to a thirdcompressive force through the fourth range of motion.

In various embodiments, the trigger assembly may comprise one or moredetent features and/or other kind of feature(s) to provide an audibleand/or tactile indication of the angular position of end effector aboutthe longitudinal axis defined by sheath. Referring to FIG. 16, invarious embodiments, trigger 1024 may be pivotally attached to handpiece 1020. Trigger 1024 may comprise a living hinge 1054. In variousembodiments, the living hinge may provide an audible and/or tactileindication to the user. For example, a trigger 1024 may be squeezedtoward a pistol grip 1022 to actuate an end effector (not shown). Theliving hinge may provide the audible and/or tactile indication whentrigger 1024 is in an actuated position. Various examples of devicescomprising audible and/or tactile indicators are described in U.S.patent application Ser. No. 12/842,565, filed Jul. 23, 2010, entitled“ELECTROSURGICAL CUTTING AND SEALING INSTRUMENT”, now U.S. Pat. No.9,011,437, the disclosure of which is incorporated by reference herein.

In various embodiments, in use, end effector 40 may be inserted into apatient via a trocar to a desired position and orientation relative toan anatomical structure within the patient. In various embodiments, theuser may operate trigger 24 through the first range of motion to capturetwo layers of tissue of the anatomical structure 42, 44 when theanatomical structure has a diameter greater than about 3 mm. Asdescribed above, flanges 62, 66 cammingly act to pivot jaw 44 toward jaw42 when firing beam 60 is actuated distally by squeezing trigger 24 fromthe unactuated position to the first actuated position. Jaws 42, 44 mayapply the first compressive force to the layers of tissue capturedtherebetween when trigger 24 is in the first actuated position. Invarious embodiments, the first compressive force may compress theanatomical structure such that the inner layers of the anatomicalstructure are extruded and separated and only the outer layer of theanatomical structure is between jaws 42, 44. In various embodiments,activation button 26 may serve as a mechanical lockout against trigger24 such that a bipolar RF current may not flow to electrode surfaces 50,52 when trigger 24 is in the first actuated position.

In various embodiments, the user may operate trigger 24 through thesecond range of motion to sever the clamped tissue layers between jaws42, 44 and thermally weld the severed tissue layers. As described above,distal blade 64 severs the clamped tissue layers as firing beam 60continues to advance distally by the user squeezing trigger 24 from thefirst actuated position to the second actuated position. Jaws 42, 44 mayapply the second compressive force to the layers of tissue capturedtherebetween when trigger 24 is in the second actuated position. Invarious embodiments, the second compressive force may allow the innersevered tissue layer portions directly contact each other. With jaws 42,44 applying the second compressive force to the severed tissue layerportions, electrode surfaces 50, 52 are activated with bipolar RF energyby the user depressing activation button 26. As described above, abipolar RF current flows between firing beam 60 and electrode surfaces50, 52 through the compressed regions of severed tissue layer portionsto thermally welds the tissue layer portions on one side of firing beam60 together and the tissue layer portions on the other side of firingbeam 60 together. In various embodiments, the inner severed tissue layerportions of the anatomical structure may be thermally welded to eachother. In various embodiments, activation button 26 may serve as amechanical lockout against trigger 24 such that a bipolar RF current maynot flow to electrode surfaces 50, 52 unless trigger 24 is in the secondactuated position and button 26 is being pressed simultaneously.

In various embodiments, in use, end effector 40 may be inserted into apatient via a trocar to a desired position and orientation relative toan anatomical structure within the patient. In various embodiments, theuser may operate trigger 24 through the third range of motion to capturetwo layers of tissue of the anatomical structure 42, 44 when theanatomical structure has a diameter up about 3 mm. As described above,flanges 62, 66 cammingly act to pivot jaw 44 toward jaw 42 when firingbeam 60 is actuated distally by squeezing trigger 24 from the unactuatedposition to the third actuated position. The user may continue tooperate trigger 24 through the third range of motion to sever theclamped tissue layers between jaws 42, 44 and thermally weld the severedtissue layers. As described above, distal blade 64 severs the clampedtissue layers as firing beam 60 continues to advance distally by theuser squeezing trigger 24 from the first actuated position to the thirdactuated position. Jaws 42, 44 may apply the third compressive force tothe layers of tissue captured therebetween when trigger 24 is in thethird actuated position.

With jaws 42, 44 applying the third compressive force to the severedtissue layer portions, electrode surfaces 50, 52 are activated withbipolar RF energy by the user depressing activation button 26. Asdescribed above, a bipolar RF current flows between firing beam 60 andelectrode surfaces 50, 52 through the compressed regions of severedtissue layer portions to thermally welds the tissue layer portions onone side of firing beam 60 together and the tissue layer portions on theother side of firing beam 60 together. In various embodiments,activation button 26 may serve as a mechanical lockout against trigger24 such that a bipolar RF current may not flow to electrode surfaces 50,52 unless button trigger is in the third actuated position and button 26is being pressed simultaneously.

As described above, in various embodiments, electrosurgical instrument10 may comprise a trigger assembly operable to control jaws 44, 42 tothereby selectively compress tissue between jaws 42, 44 at variouscompressive forces. Various embodiments, of the trigger assembly andother components of hand piece 20 are described in greater detail below,while further examples will be apparent to those of ordinary skill inthe art in view of the teachings herein.

As described above, in various embodiments, firing beam 60 may beadvanced distally by squeezing trigger 24 toward pistol grip 22 to theactuated position; while firing beam 60 may be retracted proximally byreleasing trigger 24 and/or by actively moving trigger 24 away frompistol grip 22 to the unactuated position. In various embodiments, thetrigger assembly may comprise a yoke to couple trigger 24 to firing beam60. In various embodiments, the trigger assembly may further comprise alink arm to couple trigger 24 to firing beam 60. Of course, firing beam60 may be moved in any other suitable fashion.

In various embodiments, an electrosurgical instrument may generallycomprise a shaft comprising a proximal end and a distal end, an endeffector extending from the distal end of the shaft, wherein the endeffector is operable to grasp tissue, a hand piece extending from theproximal end, wherein the hand piece comprises a pistol grip and atrigger assembly extending from the hand piece, wherein the triggerassembly comprises a trigger movable relative to the pistol grip betweenan unactuated position and a first actuated position and a secondactuated position, wherein the trigger is operable to control the endeffector to selectively grasp tissue at a first compressive force whenthe trigger is in the first actuated position and a second compressiveforce when the trigger is in the second actuated position.

In various embodiments, referring to FIGS. 6 and 7, electrosurgicalinstrument 110 may generally comprise a bypass latch or over-centermechanism configured to define a bypass pathway 113 for trigger 124. Invarious embodiments, hand piece 120 comprises pistol grip 122, bypasslatch leaf spring 111, and a trigger assembly comprising trigger 124pivotally attached to yoke 138. Trigger 124 may comprise extension arm125 comprising slot 113 defining a bypass pathway. One end of bypasslatch leaf spring 111 may be fixedly attached to hand piece 120 and thefree end of bypass latch leaf spring 111 may be disposed in slot 113. Asshown in FIG. 7, the free end of bypass latch leaf spring 111 engages afirst portion of slot 113 when trigger 124 is in the unactuated position1, a second portion of slot 113 when trigger 124 is in the firstactuated position 2, and a third portion of slot 113 when trigger 124 isin the second actuated position 3.

In use for tissues having large diameters or thicknesses, bypass latchleaf spring 111 may be configured to pass through the first actuatedposition 2 and release to or near the second actuated position 3 whenelectrosurgical instrument 110 is activated to seal the tissue betweenjaws (not shown). In this way, the user crushes the tissue at the firstactuated position 2 such that the inner tissue layers may be extrudedlaterally before end effector (not shown) is activated to cut andcoagulate the outer tissue layers at the second actuated position 3. Inuse for tissues have small diameters, bypass latch leaf spring 111 maybe configured to pass directly to the third actuated position 4 whenelectrosurgical instrument 110 is activated to capture, cut, and/or sealthe tissue between jaws (not shown). Without wishing to be bound to anyparticular theory, it is believed that electrosurgical instrumentsaccording to the present disclosure may utilize substantially similarpower and clamp force to coagulate larger blood vessels as currentultrasonic shear devices use to coagulate smaller blood vessels.

In various embodiments, referring to FIGS. 8A-G, hand piece 220 maygenerally comprise yoke 238 longitudinally slideable relative to handpiece 220, trigger 224 slideably attached to yoke 238 and rotationallyattached to hand piece 220, and link arm 236 fixedly attached to yoke238 and rotationally attached to hand piece 220. Link arm 236 maycomprise slot 233. Trigger 224 may be coupled to link arm 236 by triggerpin 216. One end of trigger pin 216 may be disposed in slot 233. Invarious embodiments, slot 233 may comprise a radial feature configuredto act as a cam and trigger pin 216 may be configured to act as a camfollower. In various embodiments, slot 233 may comprise a first portionand a second portion. In various embodiments, the first portion of slot233 may comprise a radial feature and the second portion of slot 233 maycomprise a longitudinal feature. For example, as shown in FIG. 8A, slot233 may comprise an L-shape wherein the first portion of slot 233 aextends proximally and radially from a plane including the longitudinalaxis of hand piece 220, and the first portion of slot 233 extendsparallel to the plane including the longitudinal axis of hand piece 220.

In use, referring to FIGS. 8A-G, when trigger 224 moves from anunactuated position (FIG. 8A) through the first range of motion (FIGS.8B, 8C) to the first actuated position (FIG. 8C), trigger pin 216 slidesalong the first portion of slot 233 to convert the movement of trigger224 into proximal linear movement of yoke 238. Trigger 224 may continueto move from the first actuated position through a second range ofmotion (FIG. 8D) to the second actuated position (FIG. 8D) when triggerpin 216 slides along a second portion of slot 233 to convert themovement of trigger 224 into distal linear movement of yoke 238. Invarious embodiments, yoke 238 may travel a first distance through thefirst range of motion and a second distance through a second range ofmotion. In various embodiments, the first distance may be greater thanor equal to the second distance. In various embodiments, the differencebetween the first distance and second distance may decrease thecompressive force applied to captured tissue from the first compressiveforce to the second compressive force.

Referring to FIGS. 8D-8G, when trigger 224 moves from the secondactuated position (FIG. 8D) through the third range of motion (FIGS.8E-G) to the unactuated position, a spring (not shown) may returntrigger 224 to an unactuated position where it is pivoted away from thelongitudinal axis. In various embodiments, referring to FIG. 8E, trigger224 is pivotable about a pivot point that is fixed relative to handpiece 220. When trigger 224 rotates away from the longitudinal axis,trigger pin 216 slides along the second portion of slot 233 to the firstportion of slot 233. As shown in FIG. 8F, as trigger 224 continues torotate away from the longitudinal axis, trigger pin 216 slides along thefirst portion of slot 233 to convert the movement of trigger 224 intoproximal linear movement of yoke 238. The unactuated position isillustrated in FIG. 8G.

In various embodiments, the trigger assembly may comprise mechanicalassistance to trigger 24 as it approaches the end of its return stroke.In various embodiments, it may also be desirable to provide asubstantially constant amount of resistance to the user squeezingtrigger during the entire range of motion such that the resistanceforces encountered by the user are not substantially greater duringcertain stages of the firing stroke and return stroke.

In various embodiments, referring to FIGS. 9A-G, hand piece 320 maygenerally comprise yoke 338 longitudinally slideable relative to handpiece 320, trigger 324 slidingly attached to yoke 338 and rotationallyattached to hand piece 320, and link arm 336 pivotally attached to yoke338 and rotationally attached to trigger 324. Trigger 324 may be coupledto link arm 336 by trigger pin 316 as described above. In variousembodiments, trigger 324 may be configured to act as a cam and slot 333and link 336 may comprise a projection configured to act as a camfollower 337. In various embodiments, link 336 may comprise projection337 to engage portion 325 of trigger 324 comprising trigger pin 316. Invarious embodiments, projection 337 may engage a first portion oftrigger 324 when trigger 324 is in the first actuated position and asecond portion of trigger 324 when trigger 324 is in the second actuatedposition. In various embodiments, projection 337 may comprise an angledsurface. For example, as shown in FIG. 9A, projection 337 may comprise apentagon-shape including an angled surface 337 a. In variousembodiments, angled surface 337 a of projection 337 may engage a firstportion 325 of trigger 324 when trigger 324 is in the first actuatedposition and a second portion 326 of trigger 324 when trigger 324 is inthe second actuated position.

In use, referring to FIGS. 9A-G, when trigger 324 moves from anunactuated position (FIG. 9A) through the first range of motion to thefirst actuated position (FIG. 9B), a first portion of angled surface 337a of projection 337 engages a first portion of trigger 324 to convertthe movement of trigger 324 into proximal linear movement of yoke 338.Trigger 324 may continue to move from the first actuated positionthrough a second range of motion (FIG. 9C) to the second actuatedposition (FIG. 9D) when a second portion of angled surface 337 a ofprojection 337 engages a second portion of trigger 324 to convert themovement of trigger 324 into distal linear movement of yoke 338. Asshown in FIG. 9C, in various embodiments, the second portion of angledsurface 337 a may comprise a complementary angle to the second portionof trigger 324. The complementary surface of trigger 324 may contact thecomplementary surface of projection 337 a when trigger 324 moves fromthe first actuated position through the second range of motion to thesecond actuated position. As described above, in various embodiments,yoke 338 may travel a first distance through the first range of motionand a second distance through a second range of motion such that thedifference between the first distance and second distance may decreasethe compressive force applied to captured tissue from the firstcompressive force to the second compressive force. As described above,the user may release trigger 324, and the spring (not shown) may returntrigger 324 to an unactuated position. When trigger 324 moves from thesecond actuated position (FIG. 9E) through the third range of motion(FIG. 9F) to the unactuated position (FIG. 9G), in various embodiments,trigger 324 may be coupled to link arm 336 by trigger pin 316 disposedin slot 333 to prevent trigger 324 from over travel and locking.

In various embodiments, referring to FIGS. 10A-D, hand piece 420 maygenerally comprise yoke 438 longitudinally slideable relative to handpiece 420, trigger 424 pivotally attached to yoke 338, and link arm 436pivotally attached to yoke 438. Trigger 424 may be coupled to link arm436 by trigger pin 416 disposed in trigger slot 417. Trigger 424 maycomprise a surface comprising relief notch 425 configured to act as acam and link arm 436 may comprise a projection 437 configured to act asa cam follower. A return spring (not shown) may be coupled to yoke 438by pin (not shown) configured to resiliently bias yoke 438 distally andprojection 437 of link arm 436 to contact the surface of trigger 424. Invarious embodiments, projection 437 of link arm 436 may engage thesurface of trigger 424 lacking relief notch 425 when trigger 424 is inthe first actuated position and engage relief notch 425 when trigger 424is in the second actuated position. In various embodiments, projection437 of link arm 438 may comprise a complementary shape to relief notch425. For example, as shown in FIG. 10D, projection 437 of link arm 438may comprise a complementary shape to relief notch 425.

In use, referring to FIGS. 10A-D, when trigger 424 moves from anunactuated position (FIG. 10A) through the first range of motion to thefirst actuated position (FIGS. 10B and 10C), projection 437 of link arm438 engages a surface of trigger 424 lacking relief notch 425 tocompress return spring (not shown) and convert the movement of trigger424 into proximal linear movement of yoke 438. Trigger 424 may continueto move from the first actuated position through a second range ofmotion to the second actuated position (FIG. 10D) when projection 437 oflink arm 438 engages relief notch 425 to decompress return spring (notshown), and to convert the movement of trigger 424 into distal linearmovement of yoke 438. In various embodiments, trigger pin 417 maycontact a first portion of trigger slot 417 when trigger 424 is in thefirst actuated position. Trigger pin 417 may slide along trigger slot417 through the second range of motion to a second portion of triggerslot 417 when trigger 423 is in the second actuated position. Asdescribed above, in various embodiments, yoke 438 may travel a firstdistance through the first range of motion and a second distance througha second range of motion such that the difference between the firstdistance and second distance may decrease the compressive force appliedto captured tissue from the first compressive force to the secondcompressive force. In various embodiments, as shown in FIG. 10D, thesecond distance may relate to the depth of relief notch 425 and/orlength of trigger slot 417. As described above, the user may releasetrigger 424, and trigger pin 416 may slide along trigger slot 417 to thefirst portion of trigger slot 417, and projection 437 of link are 438may rotate out of relief notch 425 to return trigger 324 to anunactuated position.

In various embodiments, referring to FIGS. 11A-C, hand piece 520 maygenerally comprise yoke 538 longitudinally slideable relative to handpiece 520, trigger 524 pivotally attached to yoke 538, and link arm 536pivotally attached to yoke 538. In various embodiments, hand piece 520may comprise a handle shroud slot 544. Trigger 524 may be coupled tolink arm 536 by trigger pin 516 disposed in trigger slot 517. Link arm537 may comprise a projection comprising a link pin 537. Link pin 537may be disposed in handle shroud slot 544. In various embodiments, linkpin 537 may slide along handle shroud slot 544. As discussed above, areturn spring (not shown) may be coupled to yoke 538 by pin (not shown)configured to resiliently bias yoke 538 distally. In variousembodiments, link pin 537 may contact a first portion of handle shroudslot 544 when trigger 524 is in the first actuated position and a secondportion of handle shroud slot 544 when trigger 524 is in the secondactuated position.

In use, referring to FIGS. 11A-C, when trigger 524 moves from anunactuated position (FIG. 11A) through the first range of motion to thefirst actuated position (FIG. 11B), link pin 537 slides along slot 544to compress return spring (not shown) and convert the movement oftrigger 524 into proximal linear movement of yoke 538. As shown in FIG.11B, link pin 537 may engage a first portion of slot 544 when trigger524 is in the first actuated position. Trigger 524 may continue to movefrom the first actuated position through a second range of motion to thesecond actuated position (FIG. 11C) when link pin 537 continues totravel along slot 544 to decompress return spring (not shown), and toconvert the movement of trigger 524 into distal linear movement of yoke538. As shown in FIG. 11B, link pin 537 may engage a second portion ofslot 544 when trigger 524 is in the second actuated position. Asdescribed above, in various embodiments, yoke 538 may travel a firstdistance through the first range of motion and a second distance througha second range of motion such that the difference between the firstdistance and second distance may decrease the compressive force appliedto captured tissue from the first compressive force to the secondcompressive force. In various embodiments, as shown in FIG. 11C, thesecond distance may relate to the configuration of slot 544 and/orlength of trigger slot 517. As described above, the user may releasetrigger 524, and trigger pin 516 may slide along trigger slot 517, linkpin 537 may slide along slot 544 to the first portion of slot 544 toreturn trigger 524 to an unactuated position. In various embodiments,slot 544 may prevent trigger 524 from over travel and locking.

In various embodiments, referring to FIGS. 14A-C, hand piece 620 maygenerally comprise yoke 638 longitudinally slideable relative to handpiece 620, trigger 624 slideably attached to yoke 638 and pivotallyattached to hand piece 620, and link arm 636 pivotally attached to yoke638 and trigger 624. In various embodiments, referring to FIGS. 12 and13, hand piece 620 may comprise slot 644 comprising first portion 644 aand second portion 644 b, and yoke 638 may comprise notch 617 comprisingfirst portion 617 a and second portion 617 b. Rear yoke pin 618 may linkhand piece 620, link arm 636, and yoke 638. A first end of rear yoke pin618 may be disposed in slot 644 and a second end of rear yoke pin may bedisposed in notch 617. In various embodiments, a first end of the rearyoke pin may engage a first portion 644 a of slot 644 when the triggeris in the first actuated position, an upward step of slot 644 betweenfirst portion 644 a and second portion 644 b when the trigger is movedthrough a second range of motion, and a second portion 644 b of slot 644when the trigger is in the second actuated position. In variousembodiments, the upward step may comprise an angled portion of the firstportion 644 a of slot 644. In various embodiments, a second end of therear yoke pin may engage a first portion 617 a of notch 617 when thetrigger is in the first actuated position and second portion 617 b whenthe trigger is in the second actuated position.

In use, referring to FIGS. 14A-C, when trigger 624 moves from anunactuated position (FIG. 14A) through the first range of motion to thefirst actuated position (FIG. 14B), the first end of the rear yoke pinmay slide along the first portion 644 a of slot 644 to convert themovement of trigger 624 into proximal linear movement of yoke 638. Thesecond end of the rear yoke pin may rest in the first portion 617 a ofnotch 617 when the trigger moves from an unactuated position through thefirst range of motion to the first actuated position. The first actuatedposition is illustrated in FIG. 14B. Trigger 624 may continue to movefrom the first actuated position through a second range of motion to thesecond actuated position (FIG. 14C) when the first end of the rear yokepin slides along the upward step of slot 644 to the second portion 644 bof slot 644 and the second end of the rear yoke pin may move from thefirst portion 617 a to the second portion 617 b of notch 617 to convertthe movement of trigger 624 into distal movement of yoke 638. In variousembodiments, yoke 638 may travel in an upward, distal direction when thefirst end of the rear yoke pin slides along the upward step of slot 644and a linear distal direction when the first end of the rear yoke pinslides along the second portion 644 b of slot 644. In variousembodiments, the angular movement yoke 638 along slot 644 relative tothe longitudinal axis and/or the movement of the rear yoke pin in notch617 during the second range of motion may provide an audible and/ortactile indication to the user that trigger (not shown) is in the secondactuated position. As discussed above, a return spring (not shown) maybe coupled to yoke 638 by pin (not shown) configured to resiliently biasyoke 638 distally. As described above, the user may release the trigger,and the first end of the rear yoke pin may slide along slot 644 from thesecond portion 644 b to the first portion 644 a of slot 644 and thesecond end of the rear yoke pin may move from the second portion 617 bto the first portion 617 a of notch 617 to return the trigger to anunactuated position. In various embodiments, slot 644 may prevent thetrigger from over travel and locking.

In various embodiments, referring to FIGS. 15A-K, hand piece 720 maygenerally comprise yoke 738 longitudinally slideable relative to handpiece 720, trigger 724 pivotally attached to yoke 738, and link arm 736fixedly attached to yoke 738. Link arm 736 may comprise slot 733.Trigger 724 may comprise trigger slot 717. Trigger 724 may be coupled tolink arm 736 by trigger pin 716. Trigger pin 716 may be disposed in linkpin 732. One end of trigger pin 716 may be disposed in trigger slot 717.One end of link pin 732 may be disposed in trigger slot 717 and theother end of link pin 732 may be disposed in slot 733. In variousembodiments, slots 717, 733 may be configured to act as a cam andtrigger pin 716 and link pin 732 may be configured to act as a camfollower. In various embodiments, slots 716, 733 may individuallycomprise a first portion and a second portion. In various embodiments,the first portion of slot 733 may comprise an angled feature and thesecond portion of slot 733 may comprise a vertical feature relative tothe longitudinal axis. For example, as shown in FIG. 15A, the firstportion of slot 733 may extend distally and vertically from a planeincluding the longitudinal axis of hand piece 220, and the secondportion of slot 733 may extend perpendicular parallel to the planeincluding the longitudinal axis of hand piece 220.

In use, referring to FIGS. 15A-K, when trigger 724 moves from anunactuated position (FIG. 15A) through the first range of motion (FIGS.15B, 15C) to the first actuated position, link pin 732 slides along thefirst portion of slot 733 to convert the movement of trigger 724 intoproximal linear movement of yoke 738. In various embodiments, link pin732 may contact a first portion of trigger slot 717 when trigger 724 isin the unactuated position and first actuated position. In variousembodiments, trigger pin 717 may not move in trigger slot 716 whentrigger 724 moves through the first range of motion. The first actuatedposition is illustrated in FIG. 15D. Trigger 724 may continue to movefrom the first actuated position through a second range of motion (FIG.15E, 15F) to the second actuated position when trigger pin 716 slidesalong a second portion of slots 717, 733 to convert the movement oftrigger 724 into distal linear movement of yoke 738. The second actuatedposition is illustrated in FIG. 15G. As described above, in variousembodiments, yoke 738 may travel a first distance through the firstrange of motion and a second distance through a second range of motionsuch that the difference between the first distance and second distancemay decrease the compressive force applied to captured tissue from thefirst compressive force to the second compressive force. In variousembodiments, as shown in FIGS. 15D, 15G, the second distance may relateto the length of trigger slot 717.

Referring to FIGS. 15G-K, when trigger 724 moves from the secondactuated position (FIG. 15G) through the third range of motion (FIGS.15H-J) to the unactuated position (FIG. 15K), a spring (not shown) mayreturn trigger 724 to an unactuated position where it is pivoted awayfrom the longitudinal axis. In various embodiments, referring to FIGS.15H and 15I, the user may release trigger 724, and trigger pin 716 mayslide along the second portion of slot 733 to the first portion of slot733 while remaining stationary in the second portion of trigger slot717. Referring to FIG. 15J, when trigger pin 716 contacts the firstportion of slot 733, trigger pin 716 may slide along the second portionof trigger slot 717 to the first portion of slot 717. As trigger 724continues to rotate away from the longitudinal axis, link pin 732 slidesalong the first portion of slots 733 to convert the movement of trigger724 into distal linear movement of yoke 738. The unactuated position isillustrated in FIG. 15K. In various embodiments, at least one of slots717, 733 may prevent trigger 724 from over travel and locking.

In various embodiments, a surgical instrument may be configured to applya compressive force to captured tissue. As described above, for example,jaws may be apply a compressive force to tissue captured therebetween.In various embodiments, referring to FIGS. 17A-H, the compressive forcemay comprise an opposing compressive force and/or a rolling compressiveforce. As shown in FIGS. 17A-D, the inner and outer layers of a vesselmay remain adhered when subjected to opposing compressive force andenergy is applied to the tissue. The adventitia layer may retract underheat resulting in an inner muscle layer bond. The inner muscle layerbond may be weaker than an adventitia-adventitia bond. In variousembodiments, jaws may apply opposing compressive force and rollingcompressive force to mechanically separate the inner and outer vessellayers when jaws close. As shown in FIGS. 17E-H, the inner and outerlayers of the vessel may separate when subject to opposing compressiveforce and rolling compressive force. The separated inner muscle layermay retract before the adventitia layer, and thereby, anadventitia-adventitia bond may be formed when energy is applied to thetissue. The separation of the inner muscle layer may reduce theoccurrence of the adventitia layer retracting during sealing by allowingthe inner muscle layer to retract inside the vessel as heat begins tobuild. In various embodiments, sealing and/or welding compressed androlled tissue layers may form a stronger adventitia-adventitia bondrelative to sealing and/or welding compressed tissue layers.

Referring to FIGS. 18A and 18B, in various embodiments, end effector 840may comprise first jaw 842 and second jaw 844. Second jaw 844 islongitudinally slideable relative to shaft 830; while first jaw 842pivots relative to shaft 830, toward and away from second jaw 844. Firstjaw 842 and second jaw 844 may comprise a plurality of teeth serrations846. The teeth serrations 846 may allow tissue to be grasped,manipulated, coagulated, and/or cut without slipping between jaws 842,844. In various embodiments, hand piece 820 may comprise connector base835 configured to retract second jaw 844 relative to shaft 830.Referring to FIGS. 19A and 19B, connector base 835 and second jaw 844may be resiliently biased to a distal position by spring 838. As shownin the insert in FIG. 19A, jaw 842 may not extend to the tip of jaw 844.Connector base is configured to cam against a ramp features in handpiece 820 to retract second jaw 844 relative to shaft 830 when firingbeam is retracted to a proximal position. Hand piece 820 may includestop members 880 located proximal to connector base 835 and spring 838.As shown in FIG. 19B, stop member 880 is configured to engage a proximalface of connector base 835 when firing beam advances distally to closejaws 842, 844. This camming capability may facilitate use of endeffector 840 to separate layers of tissue, such as, for example, theadventitia layer and inner muscle layers of a vessel. As shown in theinsert in FIG. 19B, jaw 844 may move proximally to contact the tip ofjaw 842 in the closed position. In various embodiments, longitudinalmovement of the actuator may provide pivoting of first jaw 842 relativeto shaft 830 and relative to second jaw 844 and retraction of second jaw844 relative to shaft 830.

In various embodiments, a surgical instrument may generally comprise ashaft comprising a proximal end and a distal end; an ultrasonicwaveguide at least partially positioned within the shaft, the waveguidehaving a proximal end and a distal end; an ultrasonically actuated bladepositioned at the distal end of the waveguide; a clamp arm assemblypivotally connected to the distal end of the shaft, wherein the clamparm assembly comprises at least two camming members rotationallyattached to a clamp arm, wherein the clamp arm is movable between anopen position and a closed position relative to the blade to compresstissue intermediate the clamp arm and blade when in the closed position,and wherein the at least two camming members rotate in oppositedirections when the clamp arm moves from the open position and a closedposition. In various embodiments, the at least two camming members mayselectively compress tissue at a first compressive force when a firstportion of the camming member contacts tissue and a second compressiveforce when a second portion of the camming member contacts tissue. Invarious embodiments, the first compressive force may be different fromthe second compressive force. In various embodiments, the firstcompressive force may be greater than or equal to the second compressiveforce. It may be contemplated to combine the aforementionedconfiguration with alternative energy modalities or combinations thereofas mentioned earlier in this specification.

In various embodiments, referring to FIG. 20, an end effector 910 maycomprise clamp arm assembly 941 to grip tissue and/or compress tissueagainst ultrasonic blade 964. Clamp arm assembly 941 may be pivotallyattached to the distal end of shaft 930 by pivot pin 943. In variousembodiments, clamp arm assembly 941 pivots relative to blade 964, towardand away from blade 964. As described above, actuators (not shown) mayextend through sheath 932 and be joined with clamp arm 941 and atpivotal coupling 943 such that longitudinal movement of the actuatorthrough shaft 930 provides pivoting of clamp arm 941 relative to shaft930 and relative to blade 964. Of course, clamp arm 941 may instead haveany other suitable kind of movement and may be actuated in any othersuitable fashion. In various embodiments, clamp arm assembly maycomprise at least one camming member 942, 944 rotationally attached toclamp arm 941. Each the camming member 942, 944 may independently rotatein one of a clockwise direction and a counter clockwise directionrelative to shaft 930 and blade 964 when clamp arm 941 is moved from theopen position to the closed position. In various embodiments, cammingmembers 942, 944 may rotate in opposite directions. In variousembodiments, the camming members 942, 944 may rotate in the samedirection. In various embodiments, camming members 942, 944 may rotatesimultaneously. In various embodiments, camming members 942, 944 mayrotate separately.

In various embodiments, clamp arm 941 may comprise actuating pin 917 forrotating camming member 944 relative to waveguide 964. Actuating pin 917may be located at a proximal end of camming member 944. Actuating pin917 may operatively engage with notch 916 of shaft 930 when clamp arm941 pivots to rotate camming member 944. For example, actuating pin 917may engage notch 916 when clamp arm 941 pivots toward blade 964 torotate camming member 944 counterclockwise. Actuating pin 917 may engagenotch 916 when clamp arm 941 pivots away from blade 964 to rotatecamming member 944 clockwise. In various embodiments, each cammingmember 942, 944 may comprise actuating pin to individually engage with acorresponding notch in shaft 930. In various embodiments, camming member944 may comprise actuating pin 917 to engage with notch 916 of shaft 930and gears (not shown) to operatively engage with gears (not shown) of atleast one other camming member 942, 944 such that rotational movement ofcamming member 944 rotates camming member 942. Of course, cammingmembers 942, 944 may instead have any other suitable kind of movementand may be actuated in any other suitable fashion.

In various embodiments, the camming member may selectively compresstissue at a first compressive force when a first portion of the cammingmember contacts tissue and a second compressive force when a secondportion of the camming member contacts tissue, wherein the firstcompressive force is different from the second compressive force. Invarious embodiments, the first compressive force is greater than thesecond compressive force. In various embodiments, referring to FIGS. 21Aand 21B, camming members 942, 944 may comprise a generallycircumferential tissue T contacting surface comprising at least oneprotrusion 942 a, 944 a. The protrusions 942 a, 944 a may extend abovethe surface of the camming members 942, 944, respectively. In variousembodiments, protrusion 942 a, 944 a may comprise a curved portion of agenerally comma-shape. In various embodiments, camming members 942, 944may selectively compress tissue T at a first compressive force when afirst portion of camming member 942, 944 comprising protrusion 942 a,944 a contacts tissue T and a second compressive force when a secondportion of the camming member 942, 944 lacking the protrusion contactstissue T. In various embodiments, the camming members 942, 944 maycontact the tissue T and rotationally engage the tissue T to shearand/or scrape any calcification on the external and/or internal surfacesof the tissue T.

While various embodiments described above include a pistol grip, itshould be understood that the foregoing teachings may be readily appliedto devices having various other kinds of grips. By way of example only,a variation of trigger and cam lever may be provided in accordance withthe above teachings in a device having a scissor grip. Various examplesof devices comprising a scissor grip is described in U.S. patentapplication Ser. No. 13/426,084, filed Mar. 21, 2012, entitled“ENERGY-BASED SCISSORS DEVICE”, now U.S. Pat. No. 8,974,447, thedisclosure of which is incorporated by reference herein. Other kinds ofgrips that may be combined with the above teachings will be apparent tothose of ordinary skill in the art. Furthermore, a variation of triggerand cam lever may be readily incorporated into devices having variousother kinds of end effectors, including but not limited to tissuegraspers, tissue retrieval pouch deploying instruments, surgicalstaplers, ultrasonic surgical instruments, etc.

It should also be understood that any of the devices described hereinmay be modified to include a motor or other electrically powered deviceto drive an otherwise manually moved component. Various examples of suchmodifications are described in U.S. Patent Application Publication No.2012/0116379, entitled “MOTOR DRIVEN ELECTROSURGICAL DEVICE WITHMECHANICAL AND ELECTRICAL FEEDBACK”, published May 10, 2012, now U.S.Pat. No. 9,161,803, the disclosure of which is incorporated by referenceherein. Various other suitable ways in which a motor or otherelectrically powered device may be incorporated into any of the devicesherein will be apparent to those of ordinary skill in the art in view ofthe teachings herein.

It should also be understood that any of the devices described hereinmay be modified to contain most, if not all, of the required componentswithin the medical device itself. More specifically, the devicesdescribed herein may be adapted to use an internal or attachable powersource instead of requiring the device to be plugged into an externalpower source by a cable. Various examples of how medical devices may beadapted to include a portable power source are disclosed in U.S.Provisional Application Ser. No. 61/410,603, filed Nov. 5, 2010,entitled “ENERGY-BASED SURGICAL INSTRUMENTS”, the disclosure of which isincorporated by reference herein. Various other suitable ways in which apower source may be incorporated into any of the devices herein will beapparent to those of ordinary skill in the art in view of the teachingsherein.

The devices disclosed herein may be designed to be disposed of after asingle use, or they may be designed to be used multiple times. In eithercase, however, the device may be reconditioned for reuse after at leastone use. Reconditioning may include a combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, the devicemay be disassembled, and any number of particular pieces or parts of thedevice may be selectively replaced or removed in any combination. Uponcleaning and/or replacement of particular parts, the device may bereassembled for subsequent use either at a reconditioning facility, orby a surgical team immediately prior to a surgical procedure. Those ofordinary skill in the art will appreciate that the reconditioning of adevice may utilize a variety of different techniques for disassembly,cleaning/replacement, and reassembly. Use of such techniques, and theresulting reconditioned device, are all within the scope of thisapplication.

Preferably, the various embodiments of the devices described herein willbe processed before surgery. First, a new or used instrument is obtainedand if necessary cleaned. The instrument can then be sterilized. In onesterilization technique, the instrument is placed in a closed and sealedcontainer, such as a plastic or TYVEK® bag. The container and instrumentare then placed in a field of radiation that can penetrate thecontainer, such as gamma radiation, x-rays, or high-energy electrons.The radiation kills bacteria on the instrument and in the container. Thesterilized instrument can then be stored in the sterile container. Thesealed container keeps the instrument sterile until it is opened in themedical facility. Other sterilization techniques can be done by anynumber of ways known to those skilled in the art including beta or gammaradiation, ethylene oxide, and/or steam.

Although the various embodiments of the devices have been describedherein in connection with certain disclosed embodiments, manymodifications and variations to those embodiments may be implemented.For example, different types of end effectors may be employed. Also,where materials are disclosed for certain components, other materialsmay be used. Furthermore, according to various embodiments, a singlecomponent may be replaced by multiple components, and multiplecomponents may be replaced by a single component, to perform a givenfunction or functions. The foregoing description and following claimsare intended to cover all such modification and variations.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

What is claimed is:
 1. A surgical instrument, comprising: a shaftcomprising a proximal end and a distal end; an ultrasonic waveguide atleast partially positioned within the shaft, the waveguide having aproximal end and a distal end; an ultrasonically actuated bladepositioned at the distal end of the waveguide; and a clamp arm assemblypivotally connected to the distal end of the shaft, wherein the clamparm assembly comprises at least two camming members rotationallyattached to a clamp arm, wherein the clamp arm is movable between anopen position and a closed position relative to the blade to compresstissue intermediate the clamp arm and the blade when in the closedposition, wherein the at least two camming members rotate relative tothe clamp arm to separate tissue layers when the clamp arm moves betweenthe open position and the closed position, wherein the at least twocamming members selectively compress the tissue at a first rollingcompressive force when a first portion of the camming members contactthe tissue and a second rolling compressive force when a second portionof the camming members contact the tissue, wherein the first rollingcompressive force is greater than the second rolling compressive force,and wherein the at least two camming members each comprise: acircumferential surface comprising the first portion and the secondportion, wherein the first portion comprises a protrusion, and whereinthe protrusion compresses the tissue at the first rolling compressiveforce.
 2. The surgical instrument of claim 1, wherein the at least twocamming members independently rotate relative to each other when theclamp arm moves between the open position and the closed position. 3.The surgical instrument of claim 1, wherein the at least two cammingmembers simultaneously rotate relative to each other when the clamp armmoves between the open position and the closed position.
 4. The surgicalinstrument of claim 1, wherein the at least two camming members rotatein one of the same direction and the opposite direction when the clamparm moves between the open position and the closed position.
 5. Thesurgical instrument of claim 1, wherein separating the tissue layerscomprises separating an adventitia layer from a muscular layer withoutcompromising the adventitia layer.
 6. A surgical instrument, comprising:a shaft comprising a proximal end and a distal end; an ultrasonicwaveguide at least partially positioned within the shaft, the waveguidehaving a proximal end and a distal end; an ultrasonically actuated bladepositioned at the distal end of the waveguide; and a clamp arm assemblypivotally connected to the distal end of the shaft, wherein the clamparm assembly comprises at least two camming members rotationallyattached to a clamp arm, wherein the clamp arm is movable between anopen position and a closed position relative to the blade to compresstissue intermediate the clamp arm and the blade when in the closedposition, wherein the at least two camming members rotate relative tothe clamp arm to separate tissue layers when the clamp arm moves betweenthe open position and the closed position, wherein the at least twocamming members selectively compress the tissue at a first rollingcompressive force when a first portion of the camming members contactthe tissue and a second rolling compressive force when a second portionof the camming members contact the tissue, wherein the first rollingcompressive force is greater than the second rolling compressive force,wherein the first rolling compressive force is sufficient to separate amuscular layer of the tissue from an adventitia layer of the tissue, andwherein the second rolling compressive force is sufficient forapplication of ultrasonic energy to cut the tissue and to seal thetissue via an adventitia-adventitia bond.
 7. A surgical instrument,comprising: a shaft comprising a proximal end and a distal end; anultrasonic waveguide at least partially positioned within the shaft, thewaveguide having a proximal end and a distal end; an ultrasonicallyactuated blade positioned at the distal end of the waveguide; and aclamp arm assembly pivotally connected to the distal end of the shaft,wherein the clamp arm assembly comprises at least two camming membersrotationally attached to a clamp arm, wherein the clamp arm is movablebetween an open position and a closed position relative to the blade tocompress tissue intermediate the clamp arm and the blade when in theclosed position, wherein the at least two camming members rotaterelative to the clamp arm to separate tissue layers when the clamp armmoves between the open position and the closed position, wherein the atleast two camming members selectively compress the tissue at a firstrolling compressive force when a first portion of the camming memberscontact the tissue and a second rolling compressive force when a secondportion of the camming members contact the tissue, wherein the firstrolling compressive force is greater than the second rolling compressiveforce, wherein the first portion comprises at least one protrusion, andwherein the at least one protrusion compresses the tissue at the firstrolling compressive force.
 8. The surgical instrument of claim 1,wherein at least one of the camming members comprises an actuatingmember configured to operatively engage the shaft as the clamp arm movesfrom the open position to the closed position to rotate the at least onecamming member relative to the clamp arm.
 9. A surgical instrument,comprising: a shaft comprising a proximal end and a distal end; anultrasonic waveguide at least partially positioned within the shaft, thewaveguide having a proximal end and a distal end; an ultrasonicallyactuated blade positioned at the distal end of the waveguide; and aclamp arm assembly pivotally connected to the distal end of the shaft,wherein the clamp arm assembly comprises at least two camming membersrotationally attached to a clamp arm, wherein the clamp arm is movablebetween an open position and a closed position relative to the blade tocompress tissue intermediate the clamp arm and the blade when in theclosed position, wherein the at least two camming members rotaterelative to the clamp arm to separate tissue layers when the clamp armmoves between the open position and the closed position, wherein atleast one of the camming members comprises an actuating memberconfigured to operatively engage the shaft as the clamp arm moves fromthe open position to the closed position to rotate the at least onecamming operatively engage the shaft as the clamp arm moves from theclosed position to the open position to rotate the at least one cammingmember relative to the clamp arm.
 10. The surgical instrument of claim6, wherein the at least two camming members independently rotaterelative to each other when the clamp arm moves between the openposition and the closed position.
 11. The surgical instrument of claim6, wherein the at least two camming members simultaneously rotaterelative to each other when the clamp arm moves between the openposition and the closed position.
 12. The surgical instrument of claim6, wherein the at least two camming members rotate in one of the samedirection and the opposite direction when the clamp arm moves betweenthe open position and the closed position.
 13. The surgical instrumentof claim 6, wherein separating the tissue layers comprises separating anadventitia layer from a muscular layer without compromising theadventitia layer.
 14. The surgical instrument of claim 7, wherein the atleast two camming members independently rotate relative to each otherwhen the clamp arm moves between the open position and the closedposition.
 15. The surgical instrument of claim 7, wherein the at leasttwo camming members simultaneously rotate relative to each other whenthe clamp arm moves between the open position and the closed position.16. The surgical instrument of claim 7, wherein the at least two cammingmembers rotate in one of the same direction and the opposite directionwhen the clamp arm moves between the open position and the closedposition.
 17. The surgical instrument of claim 7, wherein separating thetissue layers comprises separating an adventitia layer from a muscularlayer without compromising the adventitia layer.
 18. The surgicalinstrument of claim 9, wherein the at least two camming membersindependently rotate relative to each other when the clamp arm movesbetween the open position and the closed position.
 19. The surgicalinstrument of claim 9, wherein the at least two camming memberssimultaneously rotate relative to each other when the clamp arm movesbetween the open position and the closed position.
 20. The surgicalinstrument of claim 9, wherein the at least two camming members rotatein one of the same direction and the opposite direction when the clamparm moves between the open position and the closed position.
 21. Thesurgical instrument of claim 9, wherein separating the tissue layerscomprises separating an adventitia layer from a muscular layer withoutcompromising the adventitia layer.